There have been various types of floor systems provided in the past which have employed some form of cushioning for absorbing shock. One form of floor system that has been offered by the assignee of this invention is the so called "Thrust-A-Cushion Panel System". This sports floor system provides a shock-absorbing, fatigue-reducing flooring system ideal for active sports applications. The construction of this type of flooring system is of a type which has the finished flooring and the subfloor sections supported at spaced intervals by generally rectangular elastomeric pads integrally formed with a plurality of parallel ribs.
Another form of floor system that has been offered by the assignee of this invention is the so called "Vari-Cushion System". This type of flooring system is a specially designed cushioned sports flooring system which has the finished hardwood flooring and the subfloor sections supported at spaced interval by the same type of elastomeric pads used in the above-described "Thrust-A-Cushion Panel System". In addition, the pads rest on a continuous layer of 1/4 inch thick crosslinked closed cell polyethylene foam so as to provide two distinct levels of shock absorption. This floor system provides a smooth transition from Stage I (foam compression) through State II (pad compression). In other words, light loads on the flooring only compress the closed cell polyethylene foam whereas heavier loads compress both the foam and the pads. The transfer of forces on the flooring takes place smoothly and energy is returned to the participant in an efficient manner.
Others have also proposed various forms of floor systems having shock absorbing capabilities. For example, in U.S. Pat. No. 4,890,434 in the name of Michael W. Niese and issued on Jan. 2, 1990, a hardwood floor system is disclosed which has the subfloor sections provided with criss-cross kerf patterns formed in one of the surfaces of each subfloor section. In addition, this floor system has a plurality of elastomeric pads secured to the bottom surface of the lower floor sections to support the floor system in a free floating manner above a base such as a concrete slab. The upper portion of each pad has oppositely extending tabs for securing to the bottom surface of the lower subfloor.
Another form of floor system employing shock absorbing capabilities that has been proposed by others can be seen in U.S. Pat. No. 4,879,857 in the name of Peterson et al. and issued on Nov. 14, 1989. In this particular floor system the finished flooring is mounted on a subfloor which, in turn, is supported over a solid base such as a cement slab. In addition, a number of spaced apart individual nodule-like resilient shock absorbing members are located under the subflooring and serve to support the subflooring and the playing surface on the solid base. Each of the shock absorbing members is molded as a single homogeneous unit made of a polyurethane material having the same durometer throughout. Alternatively, the shock absorbing member may have one portion made of a material having one durometer and another portion made of the same or different material having a different durometer.
Other U.S. patents showing floor systems incorporating shock absorbing capabilities are as follows:
U.S. Pat. No. 5,303,526, Niese, issued Apr. 19, 1994 PA1 U.S. Pat. No. 5,377,471, Niese, issued Jan. 3, 1995 PA1 U.S. Pat. No. 5,388,380, Niese, issued Feb. 14, 1995 PA1 U.S. Pat. No. 5,433,052, Niese, issued Jul. 18, 1995 PA1 U.S. Pat. No. 5,465,548, Niese, issued Nov. 14, 1995